Evaporation is a ______ process.

Evaporation is a ______ process.

• A. Heating
• B. Cooling
• C. Phase-change
• D. Expanding

Answer: (A)

Evaporation is a phase-change process: it involves a change of state from liquid to gas at the surface. As surface molecules gain enough energy to overcome intermolecular forces, they escape into the air as vapor. This requires energy, known as latent heat of vaporization, and can occur at temperatures below the liquid’s boiling point, making it a surface-driven process rather than a simple heating or expansion event. Boiling is a different phase-change that happens throughout the liquid when vapor pressure reaches the surrounding pressure. Evaporation can be sped up by heating, but the essential idea is the change from liquid to gas, which is why this describes the process best.

Evaporation is a phase-change process: it involves a change of state from liquid to gas at the surface. As surface molecules gain enough energy to overcome intermolecular forces, they escape into the air as vapor. This requires energy, known as latent heat of vaporization, and can occur at temperatures below the liquid’s boiling point, making it a surface-driven process rather than a simple heating or expansion event. Boiling is a different phase-change that happens throughout the liquid when vapor pressure reaches the surrounding pressure. Evaporation can be sped up by heating, but the essential idea is the change from liquid to gas, which is why this describes the process best.